[libvirt] [PATCH 1/3] qemu: cgroup: Don't use NULL path on default backed RNGs

The "random" backend for virtio-rng can be started with no path specified which equals to /dev/random. The cgroup code didn't consider this and called few of the functions with NULL resulting into: $ virsh start rng-vm error: Failed to start domain rng-vm error: Path '(null)' is not accessible: Bad address Problem introduced by commit c6320d34637a9883e31c4081d418fc33a4277cf2 --- src/qemu/qemu_cgroup.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c index 795ad90..f649d66 100644 --- a/src/qemu/qemu_cgroup.c +++ b/src/qemu/qemu_cgroup.c @@ -587,10 +587,16 @@ qemuSetupDevicesCgroup(virQEMUDriverPtr driver, if (vm->def->rng && (vm->def->rng->backend == VIR_DOMAIN_RNG_BACKEND_RANDOM)) { VIR_DEBUG("Setting Cgroup ACL for RNG device"); - rv = virCgroupAllowDevicePath(priv->cgroup, vm->def->rng->source.file, + const char *rngpath = vm->def->rng->source.file; + + /* fix path when using the default */ + if (!rngpath) + rngpath = "/dev/random"; + + rv = virCgroupAllowDevicePath(priv->cgroup, rngpath, VIR_CGROUP_DEVICE_RW); virDomainAuditCgroupPath(vm, priv->cgroup, "allow", - vm->def->rng->source.file, "rw", rv == 0); + rngpath, "rw", rv == 0); if (rv < 0 && !virLastErrorIsSystemErrno(ENOENT)) goto cleanup; -- 2.0.0